Type-writer escapement.



No. 800,799. PATENTED OCT. 3, 1905.

E. H. DODGE. TYPE WRITER ESGAPEMENT.

APPLICATION FILED MAR.10, 1902.

UNITED STATES PATENT OFFICE.

EDIVIN H. DODGE, OF HARTFORD, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS, OF ONE-THIRD TO EDMUND J. FAIRFIELD, ONE-THIRD TO AUSTIN C. DUNHAM, AND ONE-SIXTH TO PHILANDER C. ROYCE, OF HARTFORD, CONNECTICUT, AND ONE-SIXTH TO M. BRADFORD SCOTT, OF EST HARTFORD, CONNECTICUT.

' TYPE-WRITER ESCAPEMENT.

Specification of Letters iPatent.

Patented Oct. 3, 1905.

Application filed March 10, 1902. Serial No. 97,425.

[0 all whom it may concern.-

Be it known that I, EDWIN H. Donen, a citizen of the United States,and a resident of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Type-VVriter Escapements, of which the following is a full, clear, and exact description, whereby any one skilled in the art can make and use the same.

My invention is more particularly adapted for use in a type-writing machine in which it is used in connection with a power-driven carriage, the escapement being connected to the cam-levers or the universal bar of the machine.

The object of my invention is to provide in a type-writing machine an escapement that will enable the carriage to be held completely under the control of the operator at whatever the rate of speed the writing may be done.

Referring to the accompanying drawings, forming part hereof, Figure 1 is a top or plan view of the escapement and related parts. Fig. 2 is a view in front elevation of the escapement with a few connected parts of the type-writing machine on which it is mounted. Fig. 3 is a like view in elevation of the escapement, showing the releasing position of the detents.

As the ordinary forms of type-writing machines in connection with which my invention as herein illustrated is embodied are well known, only so much of such a machine is illustrated as is required to make clear the relation of the escapement device to the mechanism of the type-writing machine.

In the accompanying drawings the numeral 1 denotes the rack-bar usually carried on the power-impelled carriage of atype-writingmachine, and to the frame of such machine the escapement 2 is attached in any convenient manner.

In the preferred form of my invention there is a bracket 3, which is mounted on the part 4 of the frame of a type-writing machine, and

on this bracket is mounted a rotary shaft 5 in a suitable bearing 6. A pinion 7, having its teeth in mesh with the teeth of the rack 1, is secured to the shaft, and on the same shaft is mounted an escape-wheel 8. In the preferred form and as a feature of my invention this escapewheel is provided with cylindrical teeth formed of wire and in a form which may be called a pin-wheel. These teeth 9 have curved surfaces; but the bearing-face alone of these pins need be curved to embody the advantages incident to the use of such teeth. Two pawls 12 and 14 are loosely mounted on the bracket 3 and preferablyon a common pivot, so as to swing in planes across the line of the axis of the shaft.

The normally engaged pawl 12 has a detent tooth 13 arranged to be movable across the path of movement of the teeth of the escapewheel and to hold the latter in a position of rest when the escapement is in its normal position of rest. The parts are held engaged in a measure by the tension on the power-impelled carriage. There is also a normally disengaged pawl 14 with a detent-tooth 15 located on the upper erd of the pawl, which in the preferred form is in the shape of a bent lever, the end opposite the tooth 15 being connected to a lever operated by the universal bar on the machine. This tooth 15 on the pawl 14 is so arranged as to swing forward across the movement of a tooth 9 on the escape-wheel just before the time that another tooth is about to be released by the swinging movement of the pawl 12.

As shown in Fig. 2, the pawl 14 is united to a connecting-rod 19 by means of a collar 16, which is held between two fixed collars 17 and 18, which may be clamped to the red, as by means of screws. Any other convenient way of attachment may obviously be used.

The pawl 12 is held in engagement with the teeth of the escapewheel with a yielding pressure through the medium of the pawlspring 20. WV hen in this normal position of rest, the detent-tooth 13 of the pawl 12 is in contact with and opposes the movement of a tooth on the escape-wheel and also rests against another tooth on the same wheel, in contact with which it is held through the medium of the spring 20. This spring is preferably coiled about a screw 24:, which forms the pivot on which the two pawls 12 and 14: are mounted in the preferred form of the device; but other ways of mounting and arranging the spring are within the scope of my invention.

On one of the pawls, and preferably the pawl 14, a trip 21 is mounted with its end arranged to strike the pawl 12 as the pawl 14 is swung on its pivot. This trip 21 is preferably in form of a screw passing through a projection 22 on the pawl 14.

When the pawl 14 is actuated, as by depressing the universal bar, the end of the trip strikes the pawl 12 and pushes the detent-tooth 13 out of engagement with the tooth 9 of the escapewheel. By this same movement the detenttooth 15 is swung into position in the path of rotary movement of the teeth of the escapewheel, so that when one of these teeth is released from the hold of the pawl 12 the detent-tooth on the pawl let will be in position to arrest the rotary movement of the escapewheel. This holds the carriage and the platen in the proper position to receive the impact of the type in printing. This imprint of the type upon the platen takes place while the escape-wheel, and therefore the carriage, is held from movement by the engagement of the detent-tooth 15 with atooth ot the escape-wheel, as illustrated in Fig. 3 of the drawings.

The bearing-face of the detent-tooth 15 is preferably formed so that a cam or bevel 23 is presented for engagement with the surface of a tooth of the escape-wheel. The object of this construction is to enable the pull of the carriage-spring which tends to rotate the escape-wheel in the direction of a releasing movement to help to disengage the detenttooth 15 by moving it radially outward from the center of the escape-wheel. The disengaging movement of the detent-tooth 15 on the pawl 14 enables the pawl 12 to swing back into position to engage a tooth 10 next back of the tooth it has previously engaged, the escapewheel rotating one tooth-space between the time when the detent-tooth 15 disengages a tooth on the escape-wheel and the engagement of the side of the tooth 13 With the tooth 9 of the escape-wheel. In the preferred form of this eseapement device the teeth on the escape-wheel are cylindrical as to the bearingfaces, while the holding-faces of the detentteeth on the pawls are substantially flat, the result being that there is a minimum extent of bearing-surface in contact with the parts, it being practically a line. The advantage of this construction is that the detents and detent-teeth have no knife-edges in contact with each other to cause undue wear of the parts. The return or engaging movement of the pawl 12 is caused by the pawl-spring 20, which tends to force the pawl 12 normally toward the end of the trip borne by the pawl 14.

An advantage of my invention is that the engaging parts of the detent-teeth and teeth of the escape-wheel may be hardened, so as to operate without frictional wear or such shock from the momentum of the parts as would in prior devices break the teeth that were hardened to withstand frictional wear. It is not necessary that the several parts should be made of the precise shape or that the several elements should be arranged precisely as shown in the accompanying drawings, as various modifications as to these parts and their relative arrangement with reference to each other may be made without departing from the invention, and such changes are within the intent and scope of my invention.

My invention as illustrated, described, and claimed herein is limited to the arrangement of the teeth on the escape-wheel, the form of such teeth, the arrangement of the pawls with respect to the face of the escape-wheel, and the manner in which the pawls receive the force from the escape-wheel. It is also limited to the shape of the bearing-face of the pawls and the special arrangement of the trip device on the pawls, and I do not make any broad claims to pawls mounted on the same axis and acting in connection with a rotary escape-wheel, one of said pawls having a certain movement independent of the other and one of said pawls being moved by the other, nor to the location of the movement of each of the pawls to one side of the axis of oscillation, these broad ideas having been invented by Edmund J. Fairlield, whose application was filed on the same date as that on which this application was filed.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is-

1. In combination with a rotary escapewheel having detentteeth with curved bearing-faces, a normally engaged pawl extending across the escape-wheel and in parallel relation with its face, and with its end opposing movement of a tooth on the wheel in a direction lengthwise of the pawl, a normally disengaged pawl lying without the periphery of the escape-wheel and provided with a detenttooth, and means for operating said pawls.

2. In combination with a rotary escapewheel having a series of detent-teeth upon its face and arranged concentric with the center of the wheel, a normally engaged pawl extending transversely of the wheel beyond the common center thereof and opposing movement of a tooth on the wheel in a direction lengthwise of the pawl, a normally disengaged pawl having a detent-tooth adapted to engage the detent-teeth of the escape-wheel and means for actuating the pawls.

3. In combination with an escapewheel having teeth with curved bearing-faces, a normally engaged pawl with a detent-tooth having a substantially-flat bearing-face, a normally disengaged pawl with a detent-tooth, a trip device adjustably mounted on the normally disengaged pawl and adapted to engage the normally engaged pawl, and means for actuating the normally disengaged pawl.

4. In combination with an escapewheel having cylindrical pins on its face, a normally engaged pawl with a detent-tooth arranged to oppose movement of the wheel in a direction IIO IIS

lengthwise of the pawl, a normally disengaged pawl with a detent-tooth, a trip device adjustably mounted on the normally disengaged pawl and adapted to engage the normally engaged pawl, and means for actuating the normally disengaged pawl.

5. In combination with an escape -wheel having cylindrical teeth on its face, a normally engaged pawl adapted to resist movement of the escape-wheel in a direction lengthwise of the pawl, a normally disengaged pawl, a trip device mounted on the normally disengaged pawl, and means for swinging said pawls in a direction radially of the escape-wheel.

6. In a type-writing escapement, an escapewheel with detent-teeth on the face of the wheel and each having a curved bearing-face, a normally engaged detent-pawl with a detent-tooth, a normally disengaged pawl with a detent-tooth, both of said pawls being mounted to swing on a common axis, a trip device borne on the normally disengaged pawl, and a rod connected to the normally disengaged pawl for operating it.

7. In combination with the rack of a powerdriven carriagein a type-writing machine, a rotary shaft, a pinion on said shaft with teeth engaging the rack, an escape-wheel secured to said shaft and having on its face a series of detent-teeth each having a curved bearingface, a normally engaged pawl having a detent-tooth, a spring operating to hold the normally engaged pawl in contact with a tooth of the escape-wheel, a normally disengaged pawl having a detent-tooth, said pawls mounted to swing upon a common axis, a trip device on the normally disengaged pawl, a connecting-rod connected with the normally disengaged pawl and means for reciprocating the connecting-rod.

8. In combination with the rack of a powerdriven carriage in a type-writing machine, a rotary shaft, a pinion mounted on said shaft and having teeth engaging the rack, an escapewheel secured to said shaft and having cylindrical teeth on its face, a normally engaged pawl with its end opposing rotary movement of the escape-wheel in a direction lengthwise of the pawl, a normally disengaged pawl, a pivot common to both of said pawls, a trip device mounted on the normally disengaged pawl, means for forcing the normally engaged pawl toward the disengaged pawl, and a connection between the normally disengaged pawl and the universal bar of the type-writing machine.

9. In a type-writer escapement, in combination with a rotary escape-wheel having detent-teeth, each provided with a curved surface, a normally engaged detent-pawl with its end removably held in the path of the detentteeth upon the escape-wheel at the point of movement of said teeth lengthwise of said pawl, said pawl having a swinging movement transverse to the path of movement of the teeth on the escape-wheel at the point of engagement of said teeth and pawl, a normally disengaged pawl with a detent-tooth engaging the teeth of the escape-wheel from the opposite side of engagement with said teeth by the normally engaged pawl, and means for operatively moving said pawls.

EDWIN H. DODGE.

Witnesses:

EDMUND J. FAIRFIELD, ARTHUR B. J ENKINS. 

